scholarly journals Kinetic Study of Subcritical Water Extraction of Carbohydrate from Microalgae Nannochloropsis sp.

2021 ◽  
Vol 21 (1) ◽  
pp. 11
Author(s):  
Nur Baiti Listyaningrum ◽  
Muhammad Mufti Azis ◽  
Sarto Sarto ◽  
Anis Nurdhiani Rosdi ◽  
Mohd Razif Harun
Keyword(s):  
Kinetic Model ◽  
Subcritical Water ◽  
Maximum Yield ◽  
Operating Conditions ◽  
Water Extraction ◽  
Extraction Time ◽  
Process Conditions ◽  
Total Carbohydrate ◽  
Consecutive Reaction ◽  
Microalgal Biomass

Microalgae contain a significant amount of carbohydrates that can be converted further to produce valuable compounds. To extract carbohydrates from microalgae, sub-critical water extraction (SWE) is a viable and novel method. Compared to other existing chemical and biological extraction methods, SWE is more economical, effective, and efficient in terms of process conditions. This process uses high temperature and pressure of water at just below supercritical conditions to keep water at a liquid state. This study aims to investigate the factors that affect the extraction yield of carbohydrates from microalgae Nannochloropsis sp. using the SWE process. The extraction was carried out at a temperature of 160 – 320 oC, a duration of 5 – 25 min, and microalgal biomass loading of 5 - 25% w/v. The kinetics study was conducted in an extraction time of 5 – 25 min at 200 oC and 5% (w/v) biomass loading. A simplified kinetic model based on a consecutive reaction was used to describe carbohydrate production and decomposition via SWE. It was found that the maximum yield of total carbohydrate was 18.04 g/100 g which was obtained at 200 oC, 10 min, and 5% (w/v) microalgal biomass loading. The carbohydrate concentration was decreased as the temperature, extraction time and microalgal biomass loading increased. This result indicated that the SWE is a promising extraction method for carbohydrate recovery from microalgae, and the factors investigated here had a significant effect on the extraction process. The proposed kinetic model was also able to capture the experimental data well within the range of operating conditions studied in this work. 

scholarly journals Subcritical Water Technology for Enhanced Extraction of Biochemical Compounds fromChlorella vulgaris

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
S. A. Awaluddin ◽  
Selvakumar Thiruvenkadam ◽  
Shamsul Izhar ◽  
Yoshida Hiroyuki ◽  
Michael K. Danquah ◽  
...  
Keyword(s):  
Environmental Sustainability ◽  
Subcritical Water ◽  
Operating Conditions ◽  
Biofuel Production ◽  
Extraction Time ◽  
High Yield ◽  
Process Conditions ◽  
Subcritical Water Extraction ◽  
Total Carbohydrate ◽  
Microalgal Biomass

Subcritical water extraction (SWE) technology has been used for the extraction of active compounds from different biomass materials with low process cost, mild operating conditions, short process times, and environmental sustainability. With the limited application of the technology to microalgal biomass, this work investigates parametrically the potential of subcritical water for high-yield extraction of biochemicals such as carbohydrates and proteins from microalgal biomass. The SWE process was optimized using central composite design (CCD) under varying process conditions of temperature (180–374°C), extraction time (1–20 min), biomass particulate size (38–250 μm), and microalgal biomass loading (5–40 wt.%).Chlorella vulgarisused in this study shows high volatile matter (83.5 wt.%) and carbon content (47.11 wt.%), giving advantage as a feedstock for biofuel production. The results showed maximum total carbohydrate content and protein yields of 14.2 g/100 g and 31.2 g/100 g, respectively, achieved under the process conditions of 277°C, 5% of microalgal biomass loading, and 5 min extraction time. Statistical analysis revealed that, of all the parameters investigated, temperature is the most critical during SWE of microalgal biomass for protein and carbohydrate production.

scholarly journals Subcritical Water Extraction of Chestnut Bark and Optimization of Process Parameters

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2774 ◽  
Author(s):  
Tanja Gagić ◽  
Željko Knez ◽  
Mojca Škerget
Keyword(s):  
Process Parameters ◽  
Subcritical Water ◽  
Extraction Process ◽  
Extraction Yield ◽  
Water Extraction ◽  
Bark Extract ◽  
Total Phenol Content ◽  
Process Conditions ◽  
Subcritical Water Extraction ◽  
Influence Of Process Parameters

The aim of the work was the optimization of the subcritical water extraction process of chestnut bark using Box–Behnken response surface methodology. The influence of process parameters, such as temperature, extraction time and solvent-solid ratio, on extraction yield, yield of the main compounds, total phenol content, total tannin content and antioxidant activity has been investigated. The identified compounds were ellagic and gallic acids, ellagitannins (vescalagin, castalagin, 1-o-galloyl castalagin, vescalin and castalin), sugars (maltose, glucose, fructose and arabinose) and sugar derivatives (5-HMF, furfural and levulinic acid). Finally, the optimal process conditions for obtaining the bark extract highly rich in ellagic acid and with satisfactory levels of total phenols and total tannins have been determined.

Study on Subcritical Water Extraction of Flavonoids from Scutellaria baicalenses

2013 ◽  
Vol 662 ◽  
pp. 293-296 ◽  
Author(s):  
Yan Cheng ◽  
Jing Liu ◽  
Chang An Liu
Keyword(s):  
Subcritical Water ◽  
Extraction Yield ◽  
Water Extraction ◽  
Extraction Time ◽  
Particle Sizes ◽  
Extraction Temperature ◽  
Subcritical Water Extraction ◽  
Operation Conditions ◽  
Conventional Extraction ◽  
Total Extraction

The extraction of baicalin, baicalein, wogonin and wogonoside from Scutellaria Baicalenses was performed using subcritical water. The effects of key operation conditions by varying the temperature (110-160 °C), extraction time (10-90 min), water loadings (2.0-4.0 mL)and particle sizes (>20- <100 mesh) were evaluated. The highest extraction yields of baicalin and wogonoside were obtained at extraction temperature of 160 °C, extraction time of 60 min, water loadings of 4.0 mL and 60-100 mesh. The highest extraction yields of baicalein and wogonin were obtained at extraction temperature of 110 °C, extraction time of 10 min, water loadings of 4.0 mL and 60-100 mesh. The subcritical water extraction was compared with the conventional extraction method. The total extraction yield by SCWE was higher than those obtained using ethanol as the solvent.

scholarly journals Investigation of operating conditions for soil remediation by subcritical water

2009 ◽  
Vol 15 (2) ◽  
pp. 89-94 ◽  
Author(s):  
Saeed Soltanali ◽  
Shams Hagani ◽  
Venous Rouzbahani
Keyword(s):  
Extraction Efficiency ◽  
Subcritical Water ◽  
Data Interpretation ◽  
Operating Conditions ◽  
Hot Water ◽  
Extraction Time ◽  
Limiting Factor ◽  
Transfer Resistance ◽  
Water Flows ◽  
Rate Limiting

The aim of the present research is to investigate the application of subcritical water to naphthalene removal from soils. The extraction curves obtained show no clear patterns relating the operating conditions to the extraction time. This is mainly due to anomalies that occurred during some extraction runs. The analysis of the results shows an extraction time rather constant as function of the operating conditions (pressure, temperature, and mass flow). The extraction efficiency, on the other hand, is found to increase at higher hot water flows and lower temperatures, while no dependence is recorded from the pressure or the density. The data interpretation suggests that the film transfer resistance is the extraction rate limiting factor in the flow range considered. Finally, the relationships between the extraction efficiency and the operating conditions, together with the non-achievement of 100% efficiency, seems to confirm some authors' theory on the resistance to desorption due to the presence in the soil of 'resistant' and slowly desorbing fractions, constituted by immobile fluid in pores.

Intrinsic Kinetics Study of CO Methanation on Ni-Mo-SiO2 Catalyst Prepared by Hydrothermal Method

2018 ◽  
Vol 921 ◽  
pp. 40-47
Author(s):  
Jia Ying Zhang
Keyword(s):  
Kinetic Model ◽  
Orthogonal Design ◽  
Fixed Bed ◽  
Reaction Network ◽  
Space Velocity ◽  
Operating Conditions ◽  
Least Square ◽  
Fixed Bed Reactor ◽  
Consecutive Reaction ◽  
Wide Range

A comprehensive kinetic model for methanation of syngas on Ni-Mo-SiO2catalyst was developed on a fixed bed reactor data. The CO and H2conversion, methane selectivity and yield were obtained in a wide range of operating conditions including 300 < T < 450°C, 1 < H2/CO <4 and 0.1 < P < 1.5 MPa with the total weight hourly space velocity (WHSV) of 60000 ml/h/g. A 6-step reaction scheme defined to the description of a reaction network that considers both catalytic and gas-phase as well as primary and consecutive reaction steps to predict the performance of the syngas methantion. Orthogonal design method was adopted to select test points with temperature, pressure and feed compositions as factors and the kinetic rates involved Langmuir – Hinshelwood equation kinetic model. The kinetic rate parameters were estimated using the Least Square Method by MATLAB. Comparing the experimental and model predicted data showed that presented model has a reasonable fit between the experimental data and the predicted values with average absolute relative deviation of ±9.8%.

scholarly journals Subcritical water extraction of polyphenols from endemic Algerian plants with medicinal properties

2020 ◽  
pp. 191-206
Author(s):  
Abdelmoumen Benmerzoug ◽  
Jaroslava Svarc-Gajic ◽  
Natasa Nastic ◽  
Sofiane Guettaf ◽  
Daoud Harzallah
Keyword(s):  
Traditional Medicine ◽  
Subcritical Water ◽  
Dry Weight ◽  
Water Extraction ◽  
Extraction Time ◽  
Operational Parameters ◽  
Subcritical Water Extraction ◽  
Pressure Time ◽  
Medicinal Properties ◽  
Pharmacological Potential

Ephedra alata, Ononis angustissima, and Genista saharae are endemic Algerian plants with pharmacological potential, used for centuries in traditional medicine. Herein the efficiency of subcritical water extraction (SWE) of phenols and flavonoids from these plants was evaluated by spectrophotometric assays. The most important operational parameters of the technique (temperature, pressure, time) were optimized for each plant based on phenols yield. At defined optimal extraction conditions (140?C for E. alata, 155?C for O. angustissima and G. saharae, 50 bars, 15min), maximum contents of phenols in the extracts were 16.13, 18.33, and 21.12 mg GAE/g dry weight, for E. alata, O. angustissima, and G. saharae, respectively. Considering the safety of the used solvent, excellent yields of phenols and short extraction time, subcritical water extraction can efficiently be used in exploitation of pharmacological potentials of the studied plants.

scholarly journals Effects of Temperature and Extraction Time on Avocado Flesh (Persea americana) Total Phenolic Yields Using Subcritical Water Extraction

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 159
Author(s):  
Walid I. Mazyan ◽  
Ellen O’Connor ◽  
Elia Martin ◽  
Anja Vogt ◽  
Edward Charter ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Subcritical Water ◽  
Persea Americana ◽  
Water Extraction ◽  
Extraction Time ◽  
Total Phenolic ◽  
Extraction Temperature ◽  
Subcritical Water Extraction ◽  
Two Samples ◽  
The Impact

This paper investigates the optimum extraction temperature for enhanced total phenolic yields extracted from avocado fruit flesh (Persea americana) using subcritical water extraction, as well as the impact of fruit ripeness on phenol extraction efficiency. Additionally, extraction yield against extraction time was investigated for time intervals of 10 min over an overall extraction time of 30 min. The subcritical water conditions studied were 18 bar, 87 mL/min, and temperatures of 105 °C, 120 °C, and 140 °C. The total phenolic compounds content was compared for week one avocado flesh and ripe (week four) avocado flesh, with a four-week ripening period between the two samples. The results show that extracting with subcritical water at 105 °C provides the highest phenolic compounds yields of 0.11% and 0.26% by dried mass for week one and ripe fruit (week four), respectively. The experimental results also indicate that the implementation of lower extraction temperatures on week four avocado (i.e., following the selection of week one avocados and allowing them to ripen over a period of one month) enhances the phenolic compounds extraction yields by more than four times relative to the first week’s sample extract, specifically during the first 20 min of extraction.

scholarly journals Optimisation of microalgal cultivation via nutrient-enhanced strategies: the biorefinery paradigm

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Gonzalo M. Figueroa-Torres ◽  
Jon K. Pittman ◽  
Constantinos Theodoropoulos
Keyword(s):  
Kinetic Model ◽  
Growth Dynamics ◽  
Value Added ◽  
Cost Effective ◽  
Predictive Modelling ◽  
Nitrogen And Phosphorus ◽  
Predictive Capacity ◽  
Microalgal Biomass ◽  
Microalgal Cultivation ◽  
Lipid Formation

Abstract Background The production of microalgal biofuels, despite their sustainable and renowned potential, is not yet cost-effective compared to current conventional fuel technologies. However, the biorefinery concept increases the prospects of microalgal biomass as an economically viable feedstock suitable for the co-production of multiple biofuels along with value-added chemicals. To integrate biofuels production within the framework of a microalgae biorefinery, it is not only necessary to exploit multi-product platforms, but also to identify optimal microalgal cultivation strategies maximising the microalgal metabolites from which biofuels are obtained: starch and lipids. Whilst nutrient limitation is widely known for increasing starch and lipid formation, this cultivation strategy can greatly reduce microalgal growth. This work presents an optimisation framework combining predictive modelling and experimental methodologies to effectively simulate and predict microalgal growth dynamics and identify optimal cultivation strategies. Results Microalgal cultivation strategies for maximised starch and lipid formation were successfully established by developing a multi-parametric kinetic model suitable for the prediction of mixotrophic microalgal growth dynamics co-limited by nitrogen and phosphorus. The model’s high predictive capacity was experimentally validated against various datasets obtained from laboratory-scale cultures of Chlamydomonas reinhardtii CCAP 11/32C subject to different initial nutrient regimes. The identified model-based optimal cultivation strategies were further validated experimentally and yielded significant increases in starch (+ 270%) and lipid (+ 74%) production against a non-optimised strategy. Conclusions The optimised microalgal cultivation scenarios for maximised starch and lipids, as identified by the kinetic model presented here, highlight the benefits of exploiting modelling frameworks as optimisation tools that facilitate the development and commercialisation of microalgae-to-fuel technologies.

scholarly journals Homogenate Extraction of Crocins from Saffron Optimized by Response Surface Methodology

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Yingpeng Tong ◽  
Yu Jiang ◽  
Dan Guo ◽  
Yongqiu Yan ◽  
Shiping Jiang ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Ethanol Concentration ◽  
Extraction Yield ◽  
Extraction Time ◽  
Process Conditions ◽  
Extraction Temperature ◽  
Single Factor ◽  
Extraction Voltage ◽  
Homogenate Extraction

Saffron, which has many kinds of biological activities, has been widely used in medicine, cosmetics, food, and other fields of health promotion industries. Crocins are the main component of saffron (Crocus sativus L.). At present, most of the extraction methods for crocins require long time or special instruments to complete the process and some of them are not suitable for industrial production at present. In this article, homogenate extraction technology which is a convenient and efficient method was developed for crocins extraction from saffron. Firstly, the influences of extraction voltage, extraction time, ethanol concentration, and temperature on crocins yield were studied by single factor experiments; and then response surface methodology (RSM) was used to optimize levels of four variables based on the result of single factor experiments. Results showed that the optimum extraction process conditions for crocins were as follows: extraction voltage, 110 V; ethanol concentration, 70%; extraction temperature, 57°C; and extraction time, 40 s. Based on these conditions, the extraction yield of crocins can reach 22.76% which is higher than ultrasonic extraction method. Therefore, homogenate extraction is an effective way to extract crocins from saffron with higher extraction yield and shorter extraction time.

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